What to do with a HB: The Okoboji Bridge

Okoboji Bridge over the Little Sioux River in Dickinson County- washed out after flooding. Photo taken in August 2011


In connection with my last article on Thacher truss bridges, we are going to have a look at this bridge, the Okoboji Bridge. Located four miles west of Fostoria over the Little Sioux River on 180th Avenue, this bridge is unique both in terms of its design as well as its history.  Built by the Clinton Bridge and Iron Works Company, this riveted truss bridge is the only one left in the country that is a pony Thacher truss, if one looks at its configuration and compare it with the examples mentioned in the last article. Yet the reason for the configuration is in connection with its history. It was built at its original location in 1909- over the strait connecting East and West Lake Okoboji, connecting Okoboji to the north and Arnolds Park to the south, carrying what is today US Hwy. 71. Yet the bridge was a replacement for the numerous swing bridges that had been built and rebuilt since 1859. The 1909 truss bridge was also a swing bridge that operated by machine instead of by hand, like its predecessors, made of wood and whose towers featured stayed wired cables. Pictures of that bridge can be seen here, including the bridge in its opening position. 

Okoboji Bridge today
The Okoboji Bridge at the site where the Thacher truss swing bridge once served its use. Now widened and modernized to handle more traffic. Photo taken in August 2009

While the Thacher truss bridge served as an important asset to the region, the increase in traffic- both vehicular as well as marine, combined with the coming of Hwy. 71 in 1926 made it expendable and was replaced in 1929 by a fixed span- a closed spandrel arch bridge, which was later widened and modified in 1997 as part of the plan to widen all of Hwy. 71 to eliminate the bottleneck traffic that had been common, especially in the summer time and during the Fourth of July. Yet with the bridge being in service for only 20 years, the county decided to recycle the bridge and move it to an out-of-the-way remote and present location- over the Little Sioux River on a road served by a pair of farms, each located on the opposite sides of the small meandering stream. It had served traffic until its closure for structural reasons in the early 1990s.

Yet the future of the bridge is without hesitation, in serious doubt. During my visit to Iowa in August 2011, I looked for the Okoboji Bridge, only to find, as you can see in the picture above as well as through a gallery via flickr that the bridge was a victim of flooding.  Although not as severe as the one three years earlier, the flooding in Iowa in June and July caused substantial damage and loss to many crops and houses, thanks in part to a wet and stormy winter, combined with the late spring thaw, unseasonable temperatures and above normal rainfall. In fact, the hardest hit area were along the Missouri River, where a line between Sioux City and Kansas City was covered in water, turning the river into the Red Sea, and forcing an unprecedented detour of I-29 which followed I-35 to Des Moines and then I-80 to Omaha, for its original path was all but underwater. It was unexpected that the Little Sioux River, a small meandering stream that flows quietly like a snake through the farmland would become a lake full of rushing water. And for this bridge, it stood in the way of the flood, resulting in the truss bridge being knocked off its foundation and landing right into the river, with fallen trees and debris covering it.

Upon inspecting the bridge, photographing and filming it, the bridge seemed to be in excellent shape with some damage to the flooring. Yet with some work on the bridge, which includes repairing some bridge parts and repainting it, it could be reused again, either as a vehicular or a pedestrian bridge. Given its location, it is unlikely that it will be used again at its present location but can be relocated somewhere else in the county. Dickinson County has had a good track record regarding reusing truss bridges for cost-effective purposes, as two bridges (also along the Little Sioux River) were replaced using truss bridges that had been located elsewhere, either in Okoboji or to the south. The Okoboji Bridge would be of best service when relocated. Yet whether the county and IaDOT would agree with this proposal depends on their willingness to save this unique piece of artwork and the costs that would incur in the relocating and rehabilitation process. Even though I did get a chance to talk to IaDOT and some other people about the bridge, the flood issue was foremost on their minds and it was understandable if this issue was tabled because  of that. Yet today, even with fewer resources, one can have a look at the bridge and decide how to proceed from there.

Keeping this in mind, have a look at the photos I posted on flickr and the film I produced that is available on youtube and decide for yourself if:

1. The bridge is salvageable and why,

2. What should be done with the bridge in terms of repairs and rehabilitation, and

3. Do you know of a place where this bridge would be of better service?

You can post your comments here, via facebook and through e-mail. Another person of contact would be Julie Bowers at Workin Bridges. Her contact details are found here.

Author’s note: additional photos and info can be found by clicking on the underlined words.

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